The invention relates to sound motion-picture cameras provided with a sound-recording unit which includes components which are mounted for movement between inoperative and operative positions. Such cameras utilize film provided with for example a magnetic recording track applied to the film prior to film exposure, so that sound can be recorded onto the film along with moving images.
To this end, the camera includes a sound-recording unit. The components of the recording unit which engage the motion-picture film usually include a capstan driven by a motor, a counterpressure roller which bears against the capstan and presses the film thereagainst, a recording head, and a pressure pad which presses the film against the recording head. The counterpressure roller and the capstan are disengageable, and the pressure pad and the recording head are likewise disengageable, in order to facilitate insertion and removal of film. However, when the sound-recording unit is actually utilized, these components must be engaged, to assure that the capstan transports the film with constant speed, and to assure that the recording head properly engages the audio track on the film. Usually, the recording unit is so designed that the capstan and recording head are stationary, whereas the counterpressure roller can be shifted away from the capstan, and the pressure pad away from the recording head, and then shifted back when necessary.
It is necessary to shift the movable components (e.g., the counterpressure roller and pressure pad) away from the stationary components (e.g., the capstan and recording head) for reasons other than to facilitate insertion and removal of film. In particular, it is advantageous to effect such disengagement whenever the sound-recording unit is not in operation. The counterpressure roller, in particular, is made of elastic material. However, if it is perpetually in engagement with the capstan, even when the camera is not being used at all, it will eventually undergo a permanent deformation. Such a loss of roundness can detrimentally affect the constancy of the film transport speed, and therefore the quality of the recorded sound.
To avoid such permanent deformation, it is known to couple the carrier structure upon which the counterpressure roller and pressure pad are mounted to the camera release member through the intermediary of a resilient or yieldable linkage. The linkage is so designed that when the camera release member is activated, the disengageable components of the recording unit are moved into their operative positions against spring force, and when the user of the camera lets go of the camera release member, the disengageable components return to their inoperative positions, in which they do not contact the film.
The camera release member in present day cameras is customarily a lever, slider or pushbutton. However, cameras are frequently provided, in addition, with threaded connectors for wire or cable release attachments and/or with jacks into which remote control cables can be plugged. These are provided in order that the user of the camera can operate the camera when the camera is mounted on a tripod.
With cameras of this type, when use is made of a wire release attachment or a remote control attachment, the sound-recording unit is not utilized, because the remote control attachment, or the like, is not capable of causing the disengageable components (e.g., counterpressure roller and pressure pad) of the recording unit to assume their operative positions. These movable components of the recording unit can be moved into their operative position only by the camera release member utilized for normal camera operation, which is not activated in these circumstances.
Also, certain cameras are provided with a hand grip mounted on the housing of the camera. The hand grip is mounted for movement between an operative position and an inoperative position. When it is in its operative position, it projects downwardly, for use during hand-held operation of the camera. When it is in its inoperative position, it does not project downwardly, in order not to interfere with the mounting of the camera on a tripod. However, when in its inoperative position, the hand grip is so located that it interferes with, or positively precludes, operation of the camera release member.